We request non-blocking I/O in the generic copy_splice_read, but "the tty layer doesn't actually honor the IOCB_NOWAIT flag for various historical reasons.". This means that a tty->pipe splice will happily sleep with the pipe locked forever, and any process trying to take it (due to an open/read/write/&c.) will enter uninterruptible sleep. This also masks inconsistent wake-ups (usually every second line) when splicing from ttys in icanon mode. Link: https://lore.kernel.org/linux-fsdevel/CAHk-=wimmqG_wvSRtMiKPeGGDL816n65u=Mq2+H3-=uM2U6FmA@xxxxxxxxxxxxxx/ Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@xxxxxxxxxxxxxxxxxx> --- drivers/tty/tty_io.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 06414e43e0b5..50c2957a9c7f 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -465,7 +465,6 @@ static const struct file_operations tty_fops = { .llseek = no_llseek, .read_iter = tty_read, .write_iter = tty_write, - .splice_read = copy_splice_read, .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, @@ -480,7 +479,6 @@ static const struct file_operations console_fops = { .llseek = no_llseek, .read_iter = tty_read, .write_iter = redirected_tty_write, - .splice_read = copy_splice_read, .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, -- 2.39.2
Attachment:
signature.asc
Description: PGP signature
